A greedy billionaire crashes the world economy to finance a scientist to send him into the future, where a horrible surprise awaits him.; A spy from Jupiter disguised as a human stows away on the first rocket from Earth to Mars. The pilot is a Martian spy disguised as Earthman Dan Blake whose mission is to radio back to Earth that a radiation belt with fatal effects makes attempting to reach Mars too dangerous so Earthmen will give up their attempts to reach Mars. The spy from Jupiter overcomes the Martian and radios Jupiter that travel to Mars is safe, and then radios the Martian's story back to Earth so as to discourage Earthlings from space flight.; No one had ever returned from a treasure search in the cave of the Shaggdorr on Ursa Centaurius. Bruno Krugg escapes the authorities and heads for the planet to steal the treasure. Little does he know the cave itself is a giant creature.